Air motor



Julie 16, 1931.

l. V. K. HOTT AIR MOTOR Fildoct. 4, 1927 Fig. a f

WORN/fw Patented `lune 16, 1931 perreo stares ron v. K. norm, or Darmon, ont@ Assienoajor cnn-ritmo To WILLIAM Fw. Barros anni ons-THIRD To M. swrrznre., Borri or Darmon, omo

Ara Moron.

This invention relates to an air motor and more particularly to a reversible air motor of the portable type. Y

One object of the invention is to provide a motor of this kind ywhich will be simple in its Construction, eiicient' in operation and which can be quickly and easily reversed by the manipulation of a single valve.

,A further obj ect ofthe invention is to pron vide improved means for yieldably retaining the piston blades in their ext-ended positions by air pressure.

A. further object of the invention is to provide means for automatically relieving the compressionof the air behind the forward piston as the latter approaches the exhaust port, thus preventing bach pressure on the piston.

Other objects of the invention will appear as the apparatus is describedin detail.

ln the accompanying drawings Fig. 1 is a vertical .sectional view taken centrally through a motor embodying my invention;

Fig. 2 is a transverse section taken o-n the line 2--2 of Fig. 1; Fig. 8 is a transverseV section taken through the piston andthe controlling member on the line 3-3 of Fig. 1; 4 is a section taken on the line lr- 4 of Fig. 1;V and Fig. 5 is a section taken on the line 5-5 of Fig. 1.

.ln these drawings I have illustrated one embodiment of my invention and have shown the same as comprising a casing 10 having a cylindrical body portion provided with heads 11 and 12. This casing has Within the same work chamber which is here shown as cylindrical in shape but which may, if desired, depart from a true cylindrical form. Rotatably mounted within this worh chamber is a cylindrical piston 13 which is of a diameter somewhat less than the diameter of the work chamber and is mounted eccentrically therein and so arranged that it will Contact with the circumferential wall of the work Achamber at one side thereof only, the contact between the piston and the wall of the cham; ber being limited to a relativelynarrow portion of the wall. This piston is carried by a hollow shaft 1.4 Awhich upper and lower .cylinder heads and may, if

is journaled in thedesired, be provided with anti-friction bear ings 15. The lower end of this shaft extends downwardly below is provided with a pinion 16 which meshes with a gear 17. The gear 17 has secured thereto a pinion 18 which meshes witha second gear 19 rigidly secured to an operating shaft 2() journaled in a bearing 21 in the lower portion of the head 12, this head` beinghollow to provide a housing within` which the gearing is located. The arrangement of the gearing is suoli that the operating shaft is in axial alinement with the motor shaft but is connected therewith through the gear train to reduce the speed of rotation.

` Thecircumferenmal wall of the work chamber is provided with an inlet port 22 and an exhaust port 23 these ports being arranged on the respective sides of but adjacent to that portion of the wall which is engaged by the piston. rlhe main casing 10 also has a valve chamber and, in the present instance, this valve chamber is shown as formed integral with the cylindrical body portion of the casing. Preferably the body portion of the casing has a laterally extending projection or hollow boss 24 within which the valve chamber is formedv and which is provided on opposite sides of that chamber with conduits 25 and 26 communicating respectively with the inlet port 22 and the exhaust Vport 23. The casing is also provided with an inlet opening 27leading to the valve chamber and adapted to be connected with a suitable conduit, such as a flexible hose, leading to a sourcel of supply for air under pressure. rihis inlet opening is here shown on the upper side of the valve chamber and is arranged betweenv the conduits 25 and 26. Leading from the lower side of the chamber is an exhaust opening or port 28 which is also arranged vbetween the conduitsl .25 and 26. Rotatably mounted within the valve chamber is a valve member 29 connected with which Visla rod or handle 30 extendingbeyond the valve chamber to .provide means for rotating the valve. The valve member 29 is provided .with an inlet passageway which is of such a character that when the valve member is in one position .the inlet the lower bearing 15 and opening 27' will be connected with the conduit 25 and when the valve member is in another position the inlet opening will be connected with the conduit 26. ln 'the present instance, this passageway is angular in form, as shown at 3l, and the ends thereof open through the wall ot' the valve member at substantially right angles one to the otner. The valve member also has an exhaust passageway 32 which is similar in shape to the inlet passageway and is so arranged that when the inlet opening 27 is connected through the passageway 3l of the valif'c member with the conduit 25 the exhaust opening 23 will be connected through the passageway with the conduit 26 and when the valve is turned to connect the inlet opening with the conduit 26 the conduit 25 will be connected with the exhaust opening. The piston is provided with yieldahle blades which engage the circumferential wall of the work chamber and constitute abutment-s against which the air acts. Prelierably these blaffles are arrange/l and, as here shown, the piston is provided on opposite sides thereot' with longitudi extending radial channels or guideways and 34 and blades and slidably mounted in the,` vguideways tor adial move ment, each blade ext/endl g the length of the piston. Each of the chemie s 33 and 34- is provide-d at its inner edge with a port 37 leading to the interior of the hol-- low shaft lll. lilounted in the hollow siert a controlling member or rod 38 which is preferably supported in the upper head li olzr the casing and which lV s a longitudinal bore 39 extendin0l lengthwise thereof. Furthe this controlling` member` has a circumferential groove 4() which communicates all times with the passazgewr s or ports leading to the channels 33 and 311-, .dit its outer end the bore 39 ot the member 38 connmmicates with a ronduit fil, in the present instance 'formed inl the body oi the casing, which leads to the inlet opening and ifit all times in open connnunicaticn ther-cwith. Consequently air under pres irc troduced into the bore 39 thi )ugh the groove 40 and ports 37 to the channels 33 and 34 and the blades and are yieldably pressed into engagement with the circumferential wall of the work chamber.

lVhen the valve 29 is in the position shown in the drawings the air enters the worl chamber through the conduit 25 and port 22 and acts on the blade 35 to rotate the piston in a clockwise direction, as shown in Fig. 2, and escapes through the port 23 and the conduit 26. As the piston rotates the air is confined between the converging walls et' the piston and the chamber and is compressed to such an extent that unless this compression is relieved it will offer more or less resistance to the rotation of the piston, thus decreasing the efficiency of the motor. ln order to relieve the pressure and expedite the exhaust orP the air l have provided means for by-passing the air about the blade which is approaching the exhaust port. Each bypass is normally closed to prevent the passage of air about the blades but is automatically o aened as the blade approaches the exhaust port. The by-passes may take various forms and may be controlled in various ways but l prefer to provide the piston, adjacent to each blade, with two passageways 42, which are here shown as substantially parallel wi h the blade, which communicate with the Worx chamber on the opposite sides ol the blade, and which are connected at their inner ends with the interior of the hollow shaft lll. rlhere are preferably a plurality ot pairs of passageways associated with each blade ancL spaced apart lengthwise. thereof. rllhe rod or controlling member 38 has formed therein a series of peripheral ports or chordwise recesses 43 arranged in line with the inner ends of the several sets of passageways (l Each peripheral port or recess is of such a length that it will bridge the space between the inner ends of two ot the passageways and thus connect those passageways and open the by-pass. The peripheral ports or recesses are so arranged that they will open the bypasses abouteach blade a short distance in adrance of the exhaust port and, as here shown, these ports are arranged on radial lines somewhat in advance of the ex aust port. The controlling member or rod maintains the oy-passes olf each blade clos-ed until that blade reaches a predetermined position with relation to the exhaust port, at which time the recesses 43 bridge the inner ends oie the respective pairs otl passageways 42 associated with that blade and thereby permit the air to escape from the chamber in the rear of the blade to the front of the blade, thereby expediting the exhaust o the air and relieving the pressure which would otherwise be created. The controlling member or rod 38 is normally stationary but is capable of rotation to permit the recesses i3 to be moved into positions adjacent to the inlet port 22, when the motor is reversed. lt will be understood that when the valve 29 is rotated through a quarter rotation, `to shitt the positions ont the inlet and exhaust passageways, the air will be admitted to the work chamber through the conduit 26 and the port 23, which then becomes the inlet port and the port 22 becomes the exhaust port, and by shitting the position or" the. controlling` member 38 the air back ol2 the blade will be gradually exhausted on the reverse operation in the same manner as it is exhausted on the forward operation. It is not necessary to the operation of the device in a reverse dihaustion of the air should be provided for on ict remita the reverse opera'tionbecause as high .a degree of efficiency is not necessary on th" reverse operationas on the forward operation.) Y

While I have shown' and'` described. one embodiment of my invention I wish vit to be understood that I d o not desire to be limited to the details thereof as various modlfications may occur to a person skilled inthe art.

what I claim as newl and desire to secure by Letters Patent, is: v

` l. In a portable air motor, a casing having a work chamber, a hollow shaft journaled in said casing and extending through said chamber, a piston carried by said shaft within said chamber and having radial guideways, blades mounted in said guideways for f, radial movement, said shaft having ports 1s said casing and extending through said chamber, a piston'carried by said shaft within said chamber and having radial yguideways, blades mounted in said guideways forY radial movement, said shaft having ports connecting said guideways with the interior thereof, a normally stationary member mounted in said hollow shaft and having a longitudinal bore and also having a circumferential groove connected with said bore and communicating with said ports to deliver air to said guideways at the inner edges of said blades, saidcasing having a valve chamber and inlet and exhaust openings therefor and having a conduit leading from said inlet opening to the bore in said stationary member, conduits connecting said valve chamber with said worl1 chamber, and a valve member to control the admission and exhaust of air to anl from said work chamber.

3. In a portable air motor, a casing having work chamber, a piston mounted for rotation in said chamber and arranged to engage a relatively narrow portion of the circumferential wall of said chamber at one side thereof only, said wall having inlet and exhaust ports at the respective sides of and ad- `jacent to said portion thereof, p yieldable blades carried by said piston and engaging said wall, and means controlled by the position of said piston for connecting that por- I-Iaving now fully described my invention,`

' longitudinal 'bore tion of said chamber which is in the rear of one of said blades withy that portion off said chamber whichl is between said'Vblad-e land said exhaust port as said blade approaches said exhaust port.

Ll. In a portable air motor, a casing having a work chamber, a piston mounted' for .rotation in said chamber and arranged to engage a relatively' narrow portion of the circumferential walll of said chamber at one side thereof only, said wall having inlet and exhaust ports at lthe respective sides of and adjacent to said portion thereof, yieldable blades y carried said wall, said piston having normally disconnected passageways communicating with said chamber in front of and in the rear of each of saidblades, and means for connecting said passageways as said blade approaches said exhaust port.

5. In a portable air motor, a casing having a work chamber, a piston mounted for rotation in said chamber and arranged to engage a relatively narrow portion of the circumferential wall of said chamberat one side thereof only,'said wall having inlet and exhaust ports at the respective sides of and adjacent to said portion thereof, yieldable blades carried by saidpiston and engaging said walhsaid piston having by-p asses forme therein and extending about the respective blades, and means controlled by the position of said piston to normally close said bypasses and to open the same as the respective blades approach said exhaust port.

6. .In a portable airmotor, a casing having a work chamber, a piston mounted fo-r rotation in said chamber and arranged to engage a relatively narrow portion of the circumferential wall of said chamber at one side thereof only, said wall having inlet and haust ports at the respective sides of and adjacent to said portion thereof, Vyieldable blades carried by said piston and engaging said wall, said piston having a longitudinal bore yand having passageways arranged on the respective sides of each of said blades and extending from the outer surface of said pistonto said bore, and a member mounted in the of said piston to normally close the inner `ends of said passageways but to connect said inner ends of the passageways about each blade asl said blade approaches said exhaust port.

7. In a portable air motor, a casing having a work chamber, a piston mounted for rotation in said chamber and arranged to engage a lrelatively narrow portion of the circumferential wall of said chamber at one side thereof only, said wall having inlet and exhaust ports at the respective sides of and adjacent to said portion thereof, yieldable blades .carried by said piston and engaging said wall,- said piston having a longitudinal borev andhaving passageways arranged on by said piston and engaging des the respective sides of each of said blades and extending from the outer surface of said piston to said bore, and a normally stationary member arranged in the longitudinal bore of said piston to normally close the inner' ends of said passagoways, said member having a port at that side thereof adjacent to said exhaust port to connect the inner ends of the passageways about said blade as said blade approaches sain exhaust port.

S. In a portable air motor, a casing having a vworl chamber, a piston mounted for rotation in said chamber and arranged to engage a relatively narrow portion of the circumferential Wall of said chamber at one side thereof only, said Wall having inlet and exhaust ports at the respective sides of and adjacent to said portion thereof7 yieldable blades carried by said piston and engaging said Wall, said piston having a longitudinal bore and having passageways arranged on the respective sides of each of said blades and extending from the outer surface of said piston to said bore3 and a normally stationary member arranged in the longitudinal bore of said piston to normally close the inner ends of said passageways, sai.;L member having a port at that side thereof adjacent to said exhaust port to connect the inner ends of the passageways about each blade as said blade approaches said exhaust port, said member being rotatable to move said port into a position adjacent to the inlet port When said piston is rotated in a reverse direction.

9. In a portable air motor, a casing having a Work chamber, ak piston mounted for rotation in said chamber and arranged to engage a relatively narrow portion of the circumferential wall of said chamber on one side thereof only, said Wall having inlet and exhaust ports at the respective sides of and adjacent to said portion thereof, said piston having radial channels extending lengthwise thereof, blades slidably mounted in said channels, said piston also having an axial bore and having associated with each of said blades a plurality of pairs of passageways, the passage- Ways of each pair being arranged on the respective sides of said blade and arranged to connect said Work chamber With the bore of said piston, a normally stationary rod mounted Within the bore of said piston and having in one side thereof a plurality of peripheral recesses arranged adjacent to the inner ends of the respective pairs of passageways and adapted to connect said inner ends of said passageways about that blade Which has been moved to a position adjacent to said exhaust port.

l0. In a portable air motor7 a casing having a Work chamber. a piston mounted for rotation in said chamber and arranged to engage a relatively narrow portion of the circumferential Wall of said chamber on one side thereof only, said Wall having inlet and exhaust ports at the respective sides of and adjacent to said portion thereof, said piston having an axial bore and also having longitudinally extending radial channels communicating With said bore, blades slidably mounted in said channels, said piston also having a pair of passageyvays arranged on the respective sides of each of said blades and adapted to connect said bore of said piston with said chamber in front of and in the rear of said blade, a normally stationary coni trolling member mounted in the bore of said hereto.

ION V. K. HOTT. 

